This summer, I walked into an Infrastructure as Code (IaC) flame war because I was blissfully unaware of just how broadly IaC had been reinterpreted. Reviewing the comments, it’s clear that thinking has evolved since Kief Morris’ 2016 Infrastructure as Code tomb. So, after strapping on my asbestos suit, I decided to dig into what is creating such a wide range of opinions and see if I can share some 2019 insights.
Why does IaC provoke such passion? The reason is simple: As an industry, we aspire to something that delivers on our collective vision of fully-automated, self-governing infrastructure. In the 00s we called it autonomic computing, then software defined data center (SDDC) and, now, IaC. Sadly, IaC is not it—or, more specifically, it’s not it alone.
The actual definition of IaC is way smaller than what people want it to be.
My take-away from IaC discussions is they are built around six key automation themes. Let’s take a few minutes to examine each of the themes. Then we’ll have a basis for answering “If that’s not IaC, then what is it?”
Programmatic Configuration (IaC)
Programmatic configuration captures the idea that we can define our infrastructure in a machine readable format. For example, you describe a planned cluster build in YAML to execution by a tool such as Terraform that requests the resources from your dynamic infrastructure and, hopefully, tracks that resource descriptors you get back from that request. Basically, it’s just your IaaS input format.
Dynamic Infrastructure (or IaaS)
It describes a system that allows operators to change the resource allocations via an API. It’s a critical part of the discussion because there must be a dependable way to pragmatically change the infrastructure. Some would consider this cloud; however, we should not assumes either managed services or VMs because dynamic infrastructure is much broader.
Desired State (or State Reconciler)
Desired state actively compares dynamic infrastructure to programmatic manifest and makes automatic adjustments to keep them synchronized. Typically, the idea of maintaining state is separated from configuring systems. Kubernetes and other Autoscaling cluster managers perform this role.
Deployment from Source Control (or Immutability)
It implies that all of the configuration components of the system can be stored as versioned artifacts and deployed from source. A Dockerfile that builds a container is a good example of an immutable process and the generated artifact. The repeatability offered by deploying from source control is transformative compared to past generations of operations that relied on either manual or scripted changes to production systems. Immutability is not IaC: We are focused on an generated deployment artifact rather than managing the infrastructure.
Composable (or Modular) Automation
It allows us to manage complex structures through layers of abstraction. In concept, composability is as simple as using platform plugin to script against an API.
CI/CD Pipeline
CI/CD pipeline is the glue that pulls all these pieces together to create a resilient environment by continuously adjusting the system components based on the operators’ IaC descriptions. The pipeline relies on having dynamic infrastructure managed to desired state as a target; however, it adds the critical concepts of staged changes over time to the system. Since we need to create systems that can adapt and improve over time, the CI/CD pipeline provides mechanism for controlled implementation change over time.
Together, these six concepts reflect an integrated new way to think about the infrastructure that is beyond IaC. They allow us to maintain and control our systems over time in a way that is resilient and automatic. More importantly, they bring complex infrastructure problems back into terms that people can comprehend by creating more deterministic and predictable chains of change. That allows us to keep our hands out of the infrastructure and our minds focused on what we are delivering: a continuously integrated data center.
Since all six concepts are interdependent, continuously integrated data center (CI DC) completely captures our aspirations for IaC. The term intuitively builds from source code into a fully operational infrastructure. More importantly, CI DC demands that we acknowledge the ongoing maintenance required. For that reason, I’ve embraced CI DC to replace IaC.
Does the term work for you? How do you see IaC or CI DC being delivered in 2020? I’d like to hear your thoughts.
